Thermosensitive device for automatic temperature-regulators.



W. M. FULTON. THEBMOSENSITIVE DEVICE FOR AUTOMATIC TEMPERATUREREGULATORS.

APPLICATION FILED MAR. 11, 1907.

Patented Nov. 17, 1908.

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(inventor UNITED strnriagrngrnntr OF ICE.

WESTON M. FULTON, OF KNOXVILLE, TENNESSEE, ASSIGNOR TO THE FULTONCOMPANY,

- OF KNOXVILLE, TENNESSEE,A CORPORATION OF MAINE.

THIBKOS INSITIVE DEVICE FOR AUTOMATIC TEHPERATURE-BEGULATOBB.

Specificationof Letters Patent.

Patented Nov. 17, 1908.

Application mod larch 11, 1907. Serial No. 301,723.

To all whom it may concern:

Be it known that I, WESTON M. FULTON, of Knoxville, Tennessee, haveinvented a new and useful Improvement in Thermosensitive Devices forAutomatic Temperature- Regulators, which invention is fully set forth inthe following specification.

This invention relates to improvements in thermosensitive devices forautomatic tem ferred to which will respond readily to small changes intemperature, while being capable "of operating over a widerange oftemperatures,which will give large motion and power to thepower-transmitting means operating the draft-dampers, and which will bevery durable and-efficient.

Heretofore efforts have been made to automatically control thetemperature of hot water and of steam in hot-water and steam heatin-systems by variations of vapor-pressure 0 a volatile liquid confined ina vessel which is aflected by the changes of temperature of the hotwater or steam, said vapor entering and actuating a collapsible and ex;

pansible vessel to impart movement to valves or dampers controlling theair-supply to the furnace. In operation, the chan es of temperature inthe heating fluid, suc as that of hot water, cause a variation of va ortension above-the surface of the volati e liquid in the vessel which isin immediate contact with the heat-ingfluid. The colla sible andexpansible chamber, however, w ichcommunicates with the vapor spaceabove. the volatile liquid in the containing vessel not being exposed tothe heat of the fluid surrounding the said vessel tends to retain itstemperature and that of the vapor therein unchanged. As a consequencewhen the temperature of the heating-fluid rises and the vaportensionabove the li uid increases the tension of the vapor within thecollapsible and expansible vessel being now less thanvessel. Partial,condensation of the incoming'vapor results, with a gradual rise oftemdperature part1 due-t0 latent heat liberate in the act 0 condensationand paitly heat of convectiom' Finally the temperature in the collasible and e ansible vessel rises to .that of t e vapor in t evolatilizing .vessel and the tension of vapor in the two vessels will bethe same and the first-named vessel will ex and and close the valve. Themovements 0 extension of the collapsible and ex ansible vessel thereforematerially lag behmd the changes of pressure in the vapor generator andthereby render the device sluggish and prevent it from controlling the.temperature of the heating-fluid within narrow limits of fluctuation.Likewise, fall of tem erature in the heating media is folperature of theheating medium, they also have at times erratic movements. It iswellknown that if a saturated vapor be confined in a chamber at anyarticular temperature the vapor may be coo ed considerably below thepoint of condensation of the vapor at the given pressure, provided thecontents of the chamber are not agitated. If for any reason the contentsare disturbed by agita tion, sudden condensation takes place in thevapor. This is particularly characteristic of-Wapors of alcohol,benzene, chloroform,

and volatile substances often used in' thermosensitive devices. Further,it is well-known that when a volatile liquid. in a quiescent state isgradually heated it may even attain a temperature above its'boilingpoint and when disturbed suddenly develo an ex plosive vapor pressure.Both 0 the describedconditions cause not only a delayed action in thecollapsible and expansible vessel, but, when action takes place, it isirregular and detracts from the'efiiciency of the device. 1

If it be attempted to overcome the objectionable feature of condensationin the motor vessel by maintaining its'temperature that of the heatingfluid, this temperature often attains in steam heatingsystems a degreewhlch will gradually draw the temper from the metal of the flexiblewalls of the motor vessel and decrease its resilience and lower itselastic limit, thereby resultingin a rapid deterioration of the wall,causing it to wear out and crack.

In order to overcome the above objections and secure the advantages ofmy invention, I have devised improved means whereby changes of pressureof a saturated vapor 1 from a volatile liquid, which is held in heatinterchanging relation with the fluid whose temperature is to beregulated, cause the movement of a liquid piston .to. actuate withoutdelay a collapsible and expansible vessel chlo roform is a suitableliquid for the purpose, since its vapor tension varies uniormly withinthe limits of hot-water heat .ing, and it is sensitive to slight changesof temperature. I preferably transmit the power of the vapor pressure tothe collapsible and expansible vessel through the medium of thesame-liquid as is used for supplying the vapor, though I may use adifi'er-. ent liquid for transmittin the power from that used forsupplying tl ie vapor, such as water and chloroform, two liquids ofdifferent density not miscible with each other.

The inventive idea involved may be embodied in a variety of mechanicalforms, and for the purpose of illustration, I haveshown one of theseforms in the accompanying drawings; but it is understood that suchdrawings are designed for the purpose of illustration only, and not asdefining the limits of the invention.

Figure 1 is a'perspective view of my improved' damper-regulator mountedon a boiler. Fig. 2 is a view partly in elevation andartly in brokensection, showing the regu ator detached.' Fig. 3 is a view partly inelevation and partly in central vertical section, on the line 33, ofFig. 2.

Referrin to Fig. 3, I have illustrated one form 0% regulator in whichthe body of I the regulator consists of a-lower bowl portion or member 1of cast metal, such as castiron, having threaded side openings 2 and 3.for connection with steam or hot-waterpipes, and flange 4 for securingmember 1 to an upper cap member 5 of castmetal', the walls of which arepreferably thinner than those of the bowl 1 and provided with a flan e6. The casing formed by the walls of t e bowl 1 and cap 5 is dividedinto an' upper and lower chamber by means of a d1s ed-shaped partition 7havinga flange 7 around its outer eriphery adapted to be received andheld E bowl and cap'by bolts ,8, 8. 1Gaskets of rubber or metal may beinserted between the flanges in a manner well understood for supportin Iugs 21.

etween flanges 4, '6 of the.

making the 'joints water or steam tight. Partition7 is provided withacentral threaded opening'9 for receivin a threaded tube 10 fittingwater-tight t erein. A vapor pressure ulb 11 is secured to the lower endof tube 7 to make a water-tight connection therewith, as by means ofscrew-threaded flange plates or washers 12, 12, one resting against theinner side of the top wall of the bulb and the outer one movable intoclamping position against the upper wall to help hold the same securelyon pipe 10. The end of tube 10 opens into bulb 1.1 and terminates nearthe bottom thereof.

Supported on partition plate 7 within the upper chamber of the casing isa collapsible and expansible vessel 13 havin a flexible corrugated outerside wall and rigid end walls 14 and 15. The lower wall 14 is deeplyreentering and forms a dead air-space above the top wall 7 of the bowl1, the function of which will clearly appear below. The end wall 14 issecured to the upper end of pipe 10 q end-wall 15 when thevessel iscollapsed to the requisite degree. A flan e plate 18 made fast to endwall 15 as by so dering or brazing, receives the screw threaded end of aplunger 19 which transmits the movements of the flexible wall 13 topower transmitting-' means operating, for example, the dampers of afurnace, as shown in Fig. 1.

In the drawings I have shown my regulator in connection with a leversupporting rocker and compensating device which forms the subject-matterof my co-pending application Sr. No. 298,713, filed January 30th,1906,and only'so much of the rocker and compensating device will be heredescribed as is necessary to a proper understanding ot'the same, as theyare not a part of theinvention herein claimed. It is to be understood,however,

that my regulator is not restricted to use with such rocker andcompensating device, as it is capable of use independently of thesedevices and in other relations. The rocker 20 comprises a casting havingside wallsand a connectin top member, and is hinged on Standards 22receive and hold ast the damper lever 23 by aid of a set screw 24. Oneend of the rocker 20 is made narrow for the purpose of receiving the 125forked end of a spring-pressed plunger 25 working in the barrel 26 ofthe compensating I device which latter is mounted to rock in supportinlugs 27. The free end of the reguator p unger 19 is looselyconnected tothe- 3o forward end of the rocker and as it moves up Plunger 25 of thecompensating device, when the damper lever is in a horizontal position,exerts no force in avertical direction, but as soon as the lever istilted in either direction the thrust of the spring pressed plunger 25furnishes a vertical component either up or down to assist thecompression or extension of the collapsible and expansible Vessel.

-In Fig. 1 I have shown a Water-heating boiler provided with my reulator which bulb to close the lower en bowl 1 of the re communicateswith the boiler t irough its opposite and horizontally displacedopenings 2-, 3, by means of small conduits 28 and 29 tappin the out-flowand return pipes 30 31 of the oiler.

The damperlever 23 carries the usual counter-poise weight 32, and isconnected to the front and rear dampers of the furnace through flexibleconnections 33 and 34.

The operation of the device thus far described is as follows: The partsof the regu- ,lator having been assembled and the flexible vessel andbulb supplied with a non-inflammable volatile liquid, such aschloroform, in uanti'ty suflicient to fill the flexible vessel an tube10 and to artially fill the d of tube 10, the later is connected up withthe out-flow an return pipes 30, 31 of the boiler in the manner shown inFig. 1. The

lower opening 3 of the bowl is connected to the return pi e 31 and theupper opening 2 with the outow pipe 30. Lfind that a more satisfactoiiyflow through the bowl is thereby secured. he damperever 23 is insertedin the slot of the rocker 20 and adjusted in proper, position in.relationto the dampers and secured therein by set screw 24; The ends ofthe lever are connected to the damper-chains 33, 34 attached to thefront draft damper of the boiler and the check damper in the smoke-hoodat the rear of the boi The regulator is now set, for exam le, to

maintaln a temperature of 150 F. in the fluid passing through the bowl1, by moving weight 32 along damper-lever 23 until its pressure actingthrough the lever 23, rocker 20 and plunger 19a ainst the upper wall 15of the exible vesse just balances the u ward pressure exerted againstwall 15'by t e liquid which is forced out of bulb 11 by the tension ofthe saturated va or in the space above the surface of the hquid inbowl 1. stand at level 35, for examp e. Now, if t e temperature of thewater of. the heating system rises for instance to 151 F. the vaporabove the liquid v,in the' bulb '11 will expand slightly de-' pressingand-"disturbing thealiqui and exposing a thin film on the walls, thusstartin rapid evaporation. The vapor so forme will exert an increasedpressure upon the surface of the liquid, lower its level to line 36, forexample, and force some of the liquid out throu h pipe '10 up into theflexibe reduced, checking combustion and thereby lowering thetemperature of the heating fluid to the original temperature of.150 F.The combustion of fuel being this arrested, the temperature of the waterin the heating system will soon begin to fall, whereupon the vapor inbulb 11 will be somewhat cooled and thus permit condensation to takeplace under the pressure exerted by weight 32 against end wall 15 of theflexible vessel, as alreadypointed out, and some of the li uid in thevessel will thus be forced back into bulb 11 so that the level of theliquid will now occupy line 35, and the dampers of the boiler will beshifted in the opposite direction to that just described, and ithcrebypermit a further combustion of fuel.

It is to be observed that in the operation of my regulator justdescribed themovement of the up er wall of the flexible vessel instantlyfo lows the changes in tension of the vapor above the surface of thevolatile liquid in bulb 11, and therefore the changes of temperature ofthe fiui'l surrounding the bulb. All slu ishness 05 action in my deviceis avoided. There i. no tendency for the vapor in the presence of itsliquid to tend towards slugglshness in condensing and reforming, as thetemperature is s owly raised or lowered, for the reason that by virtueof the construction of the regulator the liquid in contact with thevapor is agitated the moment there is a change of temperature of theheating fluid surrounding the bulb 11. This will be evident from thefact that when, for instance, the temperature of the heating fluidrises, the vapor in bulb 11 expands according to the well-known law ofexpansion of vapors. This expansion is independent of the expansionaccompanied by formation of additional vaporfrom the surface of theliquid and immediately effects a transfer of some of the liquid in bulb11 through pipe 10 to the flexible vessel .and thereby sets intoagitation the liquid in the bulb. This transfer of liquid and resultingagitation is further has- I tened by the rapid formation of vapor fromthe capillary film of li uid wetting the sides of the bulb as the receing surface of liquid falls to line 36. The cumulative effect of theresultin vapor pressure cooperates with that due to t e expansion ofvapor in the bulb to set up a flow of the liquid and maintain itsagitation. The vapor incontact with its liquid has thereforelittle'opportunity to act sluggishly in forming or condensing as thebelow the bottom wall 14 of the collapsible vessel and above thepartition wall 7 which separates the cap 1 from the cap The air in thisspace acts to prevent the flexible vessel from receiving heat from plate.7 and assists thereby in maintaining this vessel at a lower temperaturethan that of the heating fluid in the bowl 1. To further assist inreduclng the temperature of the flexible vessel the I walls of theprotecting cap are made thin to facilitate the escape of heat radiatedfrom the extended surfaces .of the deep corrugations of the vessel.

The liquid in the flexible vessel remains at all times relatively coolas compared with the liquid in bulb 11. As a result the cooler liquid inthe upper vessel continually tends to descend and that in the bulb to'rise to take its place. Even While the temperature of the heating fluidis stationary the liquid 1n the bulb is continually agitated. Thiscooler body of liquid in the upper vessel per.- forms another importantfunction in that it hastens the action of the regulator in responding toa falling temperature of the heating fluid. When the temperature of thelatter falls contraction takes place in the vapor of the bulb followedby an inflow of cooler liquid from the upper vessel which causes a morerapid condensation of vapor and facilitates and hastens-contraction ofits volume and collapsing of the vessel. From what precedes it isevident that whether the temperatue of the circulating fluid. in bowl 1rises or falls even in a slight degree, the

regulator promptly responds to such-changes.

Y'Vhile I have described my improvement as peculiarly adapted for use indamper regulators I desire it to be understood that it may be used inother relations, such as to control a valve in a steam or hot-water pipewhere the flow of such fluid is dependent on the, variationoftemperature of the same or another fluid.

, What is claimed is 1. In a thermosensitive device of the char-' saidchamber. 1

2. In athermosensitive device of the character described, a fluidpressure chamber, a casing for the same having an inlet and outlet, a.collapsible and eXpansible vessel having deep corrugations to facilitateradiation of heat, and a reentering bottom forming with one wall of saidcasing a dead air-space, a conduit connecting said vessel and chamber,and a cap inclosing said vessel.

3. In a thermosensitive device of the char acter described, thecombination of a vapor pressure chamber having a casing provided with aninlet and'outlet for a heating fluid, a collapsible and expansiblevessel having a reentering bottom wall mounted above said casing andforming therewith a closed air chamber, a conduit connecting saidchamber and vessel, said vessel conduit and a portion of said chamberbeing filled with chloroform v subject to the changes of vapor pressurein said chamber to actuate said vessel.

4. In a thermosensitive device of the character described, thecombination of a .fiuid pressure chamber having therein chloroformpartly filling the same, a collapsible and expausible vessel havingcommunication therewith and filled with a liquid having a density thatof or less than chloroform, a casing for said chamber having a heatingfluid inlet and outlet, one wall of said casing forming with one wall ofsaid vessel a closed air chamber.

5. In a thermosensitive device of the character described, thecombination of a fluid pressure chamber having therein chloroform partlyfilling the same, a collapsible'and ex pansible vessel havingcommunication therewith and filled with a liquid having a density thatof or less than chloroform, a casing for said chamber having a heatingfluid inlet and outlet, one wall of said casing forming with one wall ofsaid vessel a closed air chamber,

and a. casing for said vessel having thin walls for dissipating heat. I

6. In a thermosensitive device of the character described, thecombination of a thermosensitive fluid-containing receptacle subject tothe changes of temperature of a heating medium, a fluid-containingcollapsible and expansible metallic motor vessel having a conduitopening into said receptacle at or near the bottom thereof and actuatedby the changes of fluid pressure in said receptacle, a

casing surrounding said receptacle, one wall of said casing inclosingwith one wall of said vessel a heat-retarding. substance.

'In testimony-whereof I have signed this specification in the presenceof two 'subscrib ing witnesses.-

WESTON M. FULTON.

Witnesses: i I

W. D. JUDKINS, E. J. HYATT.

